Modiola caroliniana (L.) G. Don, Carolina bristle mallow. Perennial herb, taprooted (rooting at basal nodes), prostrate to decumbent, to 28 cm tall, 15—90 cm long; shoots somewhat soft–hairy, stiff–pilose and with shorter stellate hairs and inconspicuous, slender erect hairs, the long hairs to 2.5 mm long and with conspicuously swollen and persistent bases.
Stems cylindric, to 4 mm in diameter, tough, green, bearing scattered single hairs and often inconspicuous, short–stellate hairs.
Leaves helically alternate, palmately dissected into 3 or 5(7) lobes and toothed, petiolate, with stipules; stipules 2, fused to stem at node, broadly ovate to triangular, 4—6 mm long, sparsely pubescent, late–deciduous; petiole channeled, several—50+ mm long; blade broadly ovate to round in outline, 15—55 mm long, slightly longer than wide, lobes obovate with broad teeth above midpoint, odd–palmately veined with principal veins raised on both surfaces.
Inflorescence flowers solitary, axillary, on slender stalk, bracteate; pedicel at anthesis 10—12 mm long increasing 2× in fruit, green turning reddish brown, flexible aging stiff, pubescent with spreading long hairs; bracteoles subtending calyx 3 (epicalyx), appearing whorled, oblanceolate and appearing petiolate, at anthesis ascending and 4—5 mm long increasing and spreading in fruit.
Flower bisexual, radial, 7—10 mm across, dish–shaped; calyx 5–lobed, green, with scattered long hairs having conspicuous, swollen bases; tube cup–shaped, at anthesis 2—3 mm long increasing in fruit, 10–veined, bumpy from stout hair bases; lobes spreading (when fully open), triangular–ovate, 3—4 mm long increasing in fruit, acute but abruptly tapered at tip, with a conspicuous midvein and covered with stout hair bases, lower surface with long hairs, internally (upper surface) with short–stellate soft hairs; petals 5, fused to expanded base of staminal tube, obovate with thick base, in range 3—4.5 mm long, ± glossy light yellowish green at base, limb dull deep yellowish pink to reddish orange, with veins of same colors radiating from base, short–ciliate on margins of base; stamens ca. 20, monadelphous (fused into column) with dome (fused portion) covering ovary + a cylindric tube; tube ca. 1 mm long, dome and tube pale green at base, free filaments ca. 1 mm long, pale yellowish green; anthers dorsifixed, monothecal, < 0.5 mm long, orange–yellow, longitudinally dehiscent; pollen orange–yellow; nectary on outside of staminal dome alternate with petal bases, nectar produced as 5 beads of liquid; pistil 1, 4 mm long; ovary superior, hidden beneath staminal column, shallowly 14—22–lobed (= ovary segments), tirelike with depressed center, 1 × 2 mm, green, densely covered above midpoint and around depression with ascending, stiff unbranched hairs and sessile glandular hairs, each ovary segment 2–chambered and with 2 incipient beaks, the chambers separated by a partition and each chamber with 1 ovule; style arising from depressed center as a column ca. 1.5 mm long, where covered with white hairs, exposed style strong red, branches = ovary segments, free, exposed portion curved among filaments, to 1.2 mm long, extending just above the longest stamens; stigmas capitate, dark red (darker than style), papillate.
Fruit schizocarpic capsule, septicidally breaking into segments (mericarps), each mericarp loculicidal and 1—2–seeded, outer rim with 2 spreading, outward–pointing, bristlelike horns per mericarp, mericarps sickle–shaped, black, with stiff hairs along edges, and wrinkles on side, horns 1.1—1.5 mm long.
Seed lopsided heart–shaped to squarish with depression at hilum, ca. 1.5 mm long, dull frosted dark brown, with hairs near hilum or both ends.
A. C. Gibson & B. A. Prigge